Sage joins his father in the rescue thriller Daylight, which opens Friday. They do not, as they did in 1990’s Rocky V, play father and son.

In this reworking of the disaster classic The Poseidon Adventure, Sage plays a petty thief on his way to prison and Sly plays a rescue worker who risks his life to help free a small group of survivors trapped in a collapsed tunnel.

“Ironically it was the movies that alienated my dad and I but that finally brought us together.”

“When I was growing up, my dad was always off making a movie somewhere. He didn’t have time for me so my brother (Seargeoh) and I were raised by our mom (Stallone’s first wife, Sasha).

“My dad insisted on registering me in karate classes so I could defend myself. I hated it. I lasted barely a year and never got further than the white belt.

“He also tried to get me into sports but I rebelled there, too. It just increased the opportunities for physical confrontations.”

The worst affront came when Sage refused to work out and sculpt his body.

“It was three wonderful months in which we actually became what we were pretending to be. We’ve remained close ever since.”

Sly has changed his image, shunning his strict workout regimen and eating foods which have helped him pack on 30 pounds. “I love my dad in this fat mode. He’s friendlier, happier and he looks like a real person. It’s easier for him to accept the way I look.”

From the time he was 16, Sage has had to fend off independent producers who tried to lure him into their exploitation movies. “They always wanted me to play a villain so they could exploit the Stallone name as they’ve done with my uncle (Frank Stallone).”

Sly’s brother Frank has made a career of starring in direct-to-video action thrillers. “Uncle Frank is the king of those cheesy exploitation videos. It’s a shame because he’s an excellent musician.

“When he saw his brother become a mega-star, Uncle Frank took it as a challenge to do the same. By watching his career, I learned that you can’t be big time if you try to do everything, but do nothing particularly well.”

Sage explains this is why he is concentrating on directing rather than acting.

“My goal is to direct my dad in a film. I have a great script by a super Italian screenwriter that my dad really likes. We’re working together on adapting it for him.”